code: def _auto_scale_before(audio_arr, datatype):
      if not isinstance(audio_arr, np.ndarray):
          raise ValueError(
              "the input audio_arr for rescaling must be numpy.ndarray."
          )
  
      if not isinstance(datatype, (np.dtype, type)):
          raise ValueError(
              "the out_datatype for rescaling must be numpy.dtype or type."
          )
  
      if np.dtype(datatype).itemsize > 4:
          raise ValueError(
              "the itemsize of out_datatype for rescaling should not greater than 4."
          )
  
file_path: nnabla/python/src/nnabla/utils/audio_utils/common.py
imports: from __future__ import division, absolute_import
  import os
  import numpy
label_desc: Use image node_id 3 for calling a global function with example usage: _auto_scale_before(audio_arr, datatype) without return types